Toxicology: Poisons and Alcohol

Toxicology Toxicology—the study of the adverse effects of chemicals or physical agents on living organisms Types: Environmental—air, water, soil Consumer—foods, cosmetics, drugs Medical, clinical, forensic

Forensic Toxicology Postmortem—medical examiner or coroner Criminal—motor vehicle accidents (MVA) Workplace—drug testing Sports—human and animal Environment—industrial, catastrophic, terrorism

Toxic substances may: - Be a cause of death - Cause impairment - Contribute to death - Explain behavior

Aspects of Toxicity 1. Dosage (how much) 2. The chemical or physical form of the substance 3. The mode of entry into the body 4. Body weight and physiological conditions of the victim, including age and gender 5. The time period of exposure 6. The presence of other chemicals in the body or in the dose

Lethal Dose LD 50 refers to the dose of a substance that kills half the test population, usually within four hours Expressed in milligrams of substance per kilogram of body weight

Toxicity Classification

Federal Regulatory Agencies Food and Drug Administration (FDA) Environmental Protection Agency (EPA) Consumer Product Safety Commission Department of Transportation (DOT) Occupational Safety and Health Administration (OSHA)

Symptoms of Various Types of Poisoning Type of Poison Symptom/Evidence Caustic poison (lye) Characteristic burns around the lips and mouth of victim Carbon monoxide Red or pink patches on the chest and thigh, unusually bright red lividity Sulfuric acid Black vomit Hydrochloric acid Greenish-brown vomit Nitric acid Yellow vomit Phosphorus Coffee-brown vomit, onion or garlic odor Cyanide Burnt almond odor Arsenic, mercury Extreme diarrhea Methyl (wood) or isopropyl (rubbing) alcohol Nausea and vomiting, unconsciousness possibly blindness

Human Specimens for Analysis Blood Urine Vitreous humor of eyes Bile Gastric contents Liver tissue Brain tissue Kidney tissue Hair/nails

Alcohol—Ethyl Alcohol (C 2 H 5 OH) Most abused drug in America About 40 percent of all traffic deaths are alcohol- related Toxic—affecting the central nervous system, especially the brain Colorless liquid, generally diluted in water Acts as a depressant Alcohol appears in blood within minutes of consumption; 30–90 minutes for full absorption Detoxification—about 90 percent in the liver About 5 percent is excreted unchanged in breath, perspiration, and urine

Rate of Absorption of Alcohol Depends on: Amount of alcohol consumed The alcohol content of the beverage Time taken to consume it Quantity and type of food present in the stomach Physiology of the consumer

BAC: Blood Alcohol Content Expressed as percent weight per volume of blood Legal limit in all states is 0.08 percent Parameters influencing BAC: Body weight Alcohol content Number of beverages consumed Time since consumption

BAC Calculation Burn-off rate of percent per hour, but can vary: Male BAC = Female BAC =  (oz)  (% alcohol) body weight  (oz)  (% alcohol) body weight

Field Tests Preliminary tests—used to determine the degree of suspect’s physical impairment and whether or not another test is justified *These simple tests are only to give an officer just cause – called ‘probable cause’ – to arrest the driver on suspicion of DUI. On average, these tests range from percent reliable in establishing that a driver is in fact under the influence of drugs or alcohol. * the driver on suspicion of DUI

Standardized Field Sobriety Tests Horizontal gaze nystagmus (HGN): follow a pen or small flashlight, tracking left to right with one’s eyes. In general, wavering at 45 degrees indicates 0.10 BAC.

Nine-step walk and turn (WAT): comprehend and execute two or more simple instructions at one time

One-leg stand (OLS): maintain balance; comprehend and execute two or more simple instructions at one time.

Blood Alcohol Content Devices AKA Breathalyzers® - work by measuring the amount of alcohol in the lungs. Because the alcohol concentration in the breath is related to that in the blood, you can figure the BAC by measuring alcohol on the breath. The ratio of breath alcohol to blood alcohol is 2,100:1. This means that 2,100 milliliters (ml) of alveolar air will contain the same amount of alcohol as 1 ml of blood.

All 50 states have now set.08% blood alcohol concentration (BAC) as the legal limit for driving under the influence (DUI) or driving while impaired (DWI). For commercial drivers, a BAC of.04% can result in a DUI or DWI conviction nationwide.